1. Field of the Invention
The present invention relates to the field of etching substrates generally and semiconductor substrates in particular; more specifically, it relates to a method of controlling the etch rate uniformity of a substrate and an apparatus for implementing the method.
2. Background of the Invention
Controlling defects during semiconductor processing and manufacturing is critical to achieving working devices in high yields. Historically the focus has been primarily on controlling defects which predominately originate from causes or foreign material on the front side (the side the devices are fabricated on) of the semiconductor substrate or wafer. An increased focus on understanding the impact on frontside devices from backside damage and backside defects is now commonplace in the semiconductor industry.
One effort to reduce backside damage and backside defects is to use wafer chucks that minimize contact with the backside of the wafer during processing. However, such chucks often have adverse effects on wafer processes such as etching and stripping that can cause other types of defects or adversely effect yield. These effects must be understood and minimized.